Abstract: An antenna device that is able to maintain the resonance frequency approximately constant despite changes in temperature to provide for stabilized communication is provided. The antenna device includes an antenna coil that receives a magnetic field transmitted from a reader/writer and a capacitor. The antenna device also includes a magnetic sheet formed at a face-to-face position with respect to the antenna coil and configured for changing the inductance of the antenna coil. The capacitor has a temperature characteristic in which the capacitance of the capacitor is changed with changes in temperature. The magnetic sheet is formed of a magnetic material having a temperature characteristic in which the inductance of the antenna coil is made to be changed with an opposite sign of change to that of the capacitance of the capacitor that is changed with changes in temperature in the working temperature range.

Abstract: An antenna circuit and a transponder with the antenna circuit are provided for forming a resonant circuit. The antenna circuit includes a substrate, an antenna conductor, and a sheet metal. The antenna conductor includes an antenna coil formed in a predetermined conductor pattern on a front surface of the substrate. The sheet metal is provided on a rear surface of the substrate opposed to the front surface of the substrate and includes a slit.

Abstract: An optical disc case, in which an optical disc is stored, wherein a face cover portion and a rear-face cover portion are connected so as to be rotated with the end portion side of each of the principal faces thereof as the center, and are configured so as to form a box-shaped appearance when the face cover portion and the rear-face cover portion are closed such that the respective principal faces of the face cover portion and the rear-face cover portion face each other, the case including: a protruding holding portion, configured to fit into a central hole formed in the optical disc to hold the optical disc, provided to the inner side of the principal face of the rear-face cover portion; and a booster antenna to which a first antenna and a second antenna are connected configured to relay a signal sent/received from one antenna to the other antenna.

Abstract: A method for reducing a resistance of an antenna circuit capable of obtaining a desired property by reducing wiring resistance to a suitable value while ensuring inductance is provided. An antenna circuit is disposed to a transponder having a carrier frequency band of 13.56 MHz. The antenna circuit is formed of a prescribed base material and two antenna conductors each of which is formed of the same conductor pattern forming an antenna coil, formed on respective front and back surfaces of the base material by electrically parallel connection. Each of the two antenna conductors has a thickness of greater than equal to 5% and less than 50% of an overall thickness formed of the two antenna conductors and the base material.

Abstract: A transponder is provided capable of having desired characteristics by a method for forming a resonance circuit, despite the fact that its cost is low and its structure is simple. An antenna circuit is provided in the transponder and comprises an antenna conductor having a predetermined conductor pattern formed on the front surface of a substrate and a sheet metal disposed on the rear surface of the substrate. A part of the sheet metal is provided with a slit so formed that its start end and terminal end are opened to the area at which the sheet metal does not exist.

Abstract: An optical disc case, in which an optical disc is stored, wherein a face cover portion and a rear-face cover portion are connected so as to be rotated with the end portion side of each of the principal faces thereof as the center, and are configured so as to form a box-shaped appearance when the face cover portion and the rear-face cover portion are closed such that the respective principal faces of the face cover portion and the rear-face cover portion face each other, the case including: a protruding holding portion, configured to fit into a central hole formed in the optical disc to hold the optical disc, provided to the inner side of the principal face of the rear-face cover portion; and a booster antenna to which a first antenna and a second antenna are connected configured to relay a signal sent/received from one antenna to the other antenna.

Abstract: An improved detectable spool for use with a ribbon includes an improved hub which includes a core and an indication member. The indication member is a generally planar metallic member that is substantially embedded in the core, with the indication member including a support and a plurality of tabs. In at least one embodiment the indication member is a monolithically formed single-piece member, while in another embodiment the indication member is a multi-component member.

Abstract: In an antenna 1a for reader/writer of an interrogator in a non-contact data carrier system comprising the interrogator and a transponder, the antenna for reader/writer of the interrogator comprises a transmitting antenna 2 for transmitting a signal to the transponder and a receiving antenna 3 for receiving a signal from the transponder, and the receiving antenna 3 is a loop coil located at a position where magnetic fields of opposite polarities are induced in the receiving antenna 3 by magnetic coupling between the receiving antenna 3 and the transmitting antenna 2 and where the magnetic fields of opposite polarities cancel out each other. Preferably, the transmitting antenna 2 is comprised of at least two loop coils 2a, 2b for generating magnetic fields of opposite polarities to each other.

Abstract: In a non-contact IC card system which transmits and receives signals between an interrogator and a transponder, a transmitter-receiver used for the interrogator includes a carrier wave oscillator capable of sweeping an oscillation frequency, a resonant wave detector for detecting the resonant frequency of the transponder among carrier waves generated by the carrier wave oscillator, and a carrier frequency holder for maintaining the oscillation frequency of the carrier wave oscillator to the frequency detected by the resonant wave detector. The system is driven with a high transmission efficiency by bring the carrier wave frequency of the interrogator into agreement with the resonant frequency of the transponder, without lowering the Q value of the resonant circuit of the transponder and without any special adjustment for controlling the resonant frequency of the transponder to the desired frequency.

Abstract: A battery-free non-contacting information card of a relatively simple arrangement which prevents an IC chip or the like from being destroyed by an excess voltage. This non-contacting information card includes a resonance circuit (3) for receiving a carrier signal (e.g., FSK signal) modulated on the basis of information supplied from a card reader/writer (2), an information processing systems (5), (6), (7) for obtaining information from the carrier signal and a rectifier systems (13) for obtaining a voltage by rectifying the carrier signal, wherein the non-contacting information card can be operated by the voltage obtained at the output side of the rectifier circuit (13). The resonance circuit (3) includes a variable capacitive element (3d).

Abstract: In a multiple loop antenna comprising a combination of a plurality of loop antennas, at least one factor among the diameter of each loop antenna, the number of turns thereof, the direction thereof, the effective permeability thereof, the relative values of electric currents of loop antennas and the phase difference of electric currents is controlled in such a way that the magnetic field intensity within the range extending from the multiple loop antenna to the distance of transmission wavelength of the multiple loop antenna decreases in inverse proportion to the n-th power (n>3) of the distance from the multiple loop antenna. This makes it possible to obtain a multiple loop antenna that has a high-intensity magnetic field within the predetermined communication zone but can steeply decrease the magnetic field intensity according to an increase in distance from the antenna and surely control the magnetic field intensity to be not greater than a stated value on the outside of the communication zone.

Abstract: In a non-contact IC card comprising a substrate and provided thereon at least an IC chip and an antenna coil formed by etching, a connecting terminal of the antenna coil and a connecting bump of the IC chip are interconnected in a face-down fashion via an anisotropic conductive adhesive layer, or interconnected by wire bonding.

Abstract: In a non-contact IC card system which transmits and receives signals between an interrogator and a transponder, a transmitter-receiver used for the interrogator comprises a distance detecting means for detecting the distance between the interrogator and the transponder, and an output control means for controlling the output level of the interrogator in accordance with the signals detected by the distance detecting means, so as to keep the receiving level of the transponder within the range of a given value. The receiving level in the transponder can be prevented from varying depending on the distance between the interrogator and the transponder, so that it becomes unnecessary to provide a protective circuit against an excessive increase of the receiving level. The optimum threshold voltage can also be prevented from varying.

Abstract: A short-distance communication antenna can satisfactorily transmit and receive an information signal within a regulation range of the radio law. Also, the short-distance communication antenna provided on a card reader/writer enables the card reader/writer to communicate with a non-contacting information card without being limited by the direction of the non-contacting information card upon reception. This short-distance communication antenna includes a plurality of magnetic poles disposed on a magnetic member and to and from which a magnetic flux is transmitted and received, and a coil for transmitting or transmitting and receiving the information signal mounted on at least one of the magnetic poles. Further, the short-distance communication antenna includes a housing having an aperture to and from which a magnetic flux is transmitted and received, and a coil for transmitting or transmitting and receiving the information signal mounted on said housing.

Abstract: A battery-free non-contacting information card of a relatively simple arrangement which prevents an IC chip or the like from being destroyed by an excess voltage. This non-contacting information card includes a resonance circuit (3) for receiving a carrier signal (e.g., FSK signal) modulated on the basis of information supplied from a card reader/writer (2), an information processing system (5), (6), (7) for obtaining information from the carrier signal and a rectifier system (13) for obtaining a voltage by rectifying the carrier signal, wherein the non-contacting information card can be operated by the voltage obtained at the output side of the rectifier circuit (13). The resonance circuit (3) includes a variable capacitive element (3d).